Fire alarm systems used in buildings and such are designed to save lives and comprise a number of components including devices such as smoke and heat sensors, and audible and visible indicators.
Indicators range from audio devices such as speakers, bells, horns, and sirens to visual devices such as incandescent lights, strobe lights, and illuminated exit signs.
For instance, prior art consists of a number of horns, sirens, bells, or voice message devices, which are strategically placed throughout a building and connected to the control panel of the fire alarm system. Upon the detection of smoke or fire, the audible device would activate and serve as an audible indicator of an emergency situation.
Alerting technology may incorporate the use of a strobe light, and like the audible device, is connected to the fire alarm control system and functions to serve as a visual indicator of an emergency situation.
The strobe light, however, has a different impact than that of the audible device. For example, the strobe light is better able to notify those with a hearing disability about the presence of an emergency. Furthermore, the light is effective in nighttime situations especially when the individual is outside the audible device's range. This is especially true when the audible device malfunctions and is unable to produce an audible sound. As a result of the mechanical failure possibility, many fire alarm systems incorporate a strobe light serving the dual purpose as detailed. In fact, many local towns or municipalities have mandated by law the use of both strobes and audible devices to alert individuals as to an emergency.
Placement of the devices in a building is generally determined by a variety of factors such as floor plans, hallways and room locations, elevator locations, exit locations, fire walls, etc. For instance, some buildings have a greater capacity to deliver sound, or reflect the strobe light based upon the buildings interior make-up.
The operating characteristics of audible and visual signals determine how occupants will hear and see them. These characteristics include the sound intensity and frequency, color of light and its intensity, flash duration, and flash repetition rate. Different buildings and environments require different needs.
The primary purpose of the fire alarm system is to alert the occupants and evacuate or lead them to safety. Sounding a general alarm tone or pre-recorded voice message accompanied with flashing lights may accomplish this goal in good visibility, but in cases where visibility is impaired or non-existent, it may not.
For example, an occupant of a hotel room may hear an evacuation signal in the middle of the night, open the room door, and must decide to take a left or right down the hallway to get to safety and has a fifty percent chance that he will select the correct direction. If he chooses the wrong direction, he may lead directly to the fire. A wrong decision may lead to toxic exposure and be fatal. When visibility is reduced or non-existent due to airborne particulates of combustion, the situation is more critical and a timely direct path to egress is monumental.
Accordingly, it is desirable to provide a method and apparatus that indicate a direct and timely path of egress in an emergency situation.